Fishing line of core-sheath structure comprising short fiber

ABSTRACT

A yarn which contains a composite yarn composed of a core part containing a short fiber and a sheath part containing a synthetic fiber filament yarn, the core part and the sheath part being integrated via fluff of the short fiber getting between or entangled with the long fibers, the specific gravity of the yarn being adjustable in the range of 1.0 or more, a fishing line containing the yarn, and a method for producing the fishing line. The present invention provides an ideal fishing line which has a strong core-sheath structure, does not allow separation or detachment of the core part and the sheath part, is easy to handle, and also is excellent in strength, weatherability, and water resistance.

TECHNICAL FIELD

The present invention relates to a fishing line having a core-sheathstructure comprising a short fiber. In more detail, the presentinvention relates to a fishing line comprising a composite yarn having ashort fiber in a core part and a long fiber in a sheath part.

BACKGROUND ART

In recent years, advancement of fishing lines has been remarkable andfishing lines of different properties tailored to various types offishing have been developed. Inter alia, braided yarns and covered yarnshaving a core-sheath structure composed of two or more kinds of fibersincluding high strength fibers, such as ultra high molecular weightpolyethylene fibers, aramid fibers, PBO fibers, polyarylate fibers andglass fibers, have attracted attention because they have high strength,durability and low rate of elongation suitable for easy and correctperception of a fish strike.

Already known as such a fishing line having a core-sheath structurecomposed of two or more kinds of fibers are as follows: a fishing linewhich is a covered yarn comprising a synthetic resin multifilament yarnas a core yarn and a twisted synthetic resin multifilament yarn as asheath yarn wound around the core yarn, the difference between the anglebetween the core yarn and the sheath yarn and the twist angle of thetwisted yarn being 25° or less thereby achieving an excellent breakingstrength and knot strength, low rate of elongation and an excellentabrasion resistance (Patent Literature 1); a fishing line comprising afluorine multifilament fiber as a core yarn and an ultra high molecularweight polyethylene fiber braided around the core yarn, which sinksbelow water surface, is not easily affected by wind etc., and has astrong abrasion resistance (Patent Literature 2); a yarn comprising aglass fiber core yarn and two or more sheath yarns made of a fiber otherthan glass fiber, the sheath yarns being braided around the core yarn,the core yarn and the sheath yarns being integrated with a binder resin,the yarn having a rate of elongation of 5% or less (Patent Literature3).

However, these conventional core-sheath fishing lines do not havesufficient degree of entwinement or binding between the core part andthe sheath part. Therefore, such fishing lines have problems that thecore part and the sheath part separate from each other and the core yarnslips off, resulting in so-called nude yarn and that friction betweenthe line guide of a fishing rod etc. and the fishing line causes thesheath part to separate and partially form an unorganized mass,so-called nep.

Meanwhile, a fishing line of which the core part and the sheath part areintegrated by means of thermal fusion bonding or a binder also has aproblem of hardening of the yarn, and resulting curliness and difficultyin handling.

In addition, a fishing line made of an ultra high strength fiber, suchas an ultra high molecular weight polyethylene filament, has arelatively small specific gravity, and therefore is easily affected bywind or tide. Furthermore, in fast tidal stream or in a deepwater area,it is difficult to quickly and accurately throw the fishing line into afishable depth range. In recent years, there is a demand from the marketfor using a fishing line with a specific gravity most suitable for aparticular situation, such as in adverse weather conditions or in anarea with rapidly changing tidal streams. In this context, developmentof a yarn with specific gravity of 1.0 or more, preferably adjustable inthe range of 1.0 or more, has been desired.

CITATION LIST

[Patent Literature 1] JP-A-09-31786 [Patent Literature 2] JP-A-08-140538[Patent Literature 3] JP-A-2004-308047

SUMMARY OF INVENTION Technical Problem

The present inventor wholeheartedly investigated to solve the problemsof conventional fishing lines and to develop a yarn having a strongcore-sheath structure, which does not develop nude yarn or nep, is easyto handle, and has specific gravity adjustable in the range of 1.0 ormore. As a result, the inventor found a surprising fact that adoption ofa short fiber is effective to solve the above-mentioned problems offishing lines sometimes used in a length of hundreds of meters. Withfurther investigations, he finally achieved the present invention.

A first objective of the present invention is to provide an idealfishing line which has a strong core-sheath structure, does not allowseparation or detachment of the core part and the sheath part, is easyto handle, and also is excellent in strength, weatherability, and waterresistance.

A second objective of the present invention is to provide a high-valueadded fishing line which has bendability, flexibility and specificgravity adjustable in the range of 1.0 or more.

A third objective of the present invention is to provide a fishing linewhich has broad utility and specific gravity adjustable in the range of1.0 or more.

A fourth objective of the present invention is to provide a fishing linewhich has a strong and stable core-sheath structure and therefore isresistant to kink, torsion, curliness in a reel, and thread jamming on aspool, achieving easy handling.

In addition, to provide a yarn excellent in robustness, durability,flexibility, etc. and suitable for producing fishing lines, guts, ropes,etc. is also an objective of the present invention.

In addition, to provide, for example, guts, ropes, etc. for tennis,badminton, etc. excellent in robustness, durability, flexibility, etc.is also an objective of the present invention. The other objectives ofthe present invention will become clear from descriptions in thisapplication.

Solution to Problem

The above-described objectives are achieved by the present invention.

That is, the present invention relates to:

(1) a fishing line comprising a composite yarn having a long fiber in asheath part and a short fiber in a core part,(2) the fishing line according to the above (1), wherein single yarns ofthe short fiber in the core part are overlapped, intertangled orintertwisted,(3) the fishing line according to the above (1) or (2), wherein thefiber length of the short fiber in the core part is 5 to 500 mm,(4) the fishing line according to any of the above (1) to (3), whereinthe specific gravity of the short fiber in the core part is 1.0 or more,(5) the fishing line according to any of the above (1) to (4), whereinthe short fiber in the core part is used for adjusting the specificgravity of the fishing line,(6) the fishing line according to any of the above (1) to (5), whereinthe short fiber in the core part comprises at least one kind selectedfrom the group consisting of a synthetic fiber, a regenerated fiber, ametal fiber, a ceramic fiber, and a glass fiber,(7) the fishing line according to any of the above (1) to (6), whereinthe short fiber in the core part comprises a polyester fiber, a glassfiber, or a fluororesin fiber,(8) the fishing line according to any of the above (1) to (7), whereinthe long fiber in the sheath part comprises an ultra high strengthfiber,(9) the fishing line according to any of the above (1) to (8), whereinthe ultra high strength fiber comprised in the long fiber in the sheathpart accounts for 12% by weight or more of the whole composite yarn,(10) the fishing line according to above (8), wherein the ultra highstrength fiber is an ultra high molecular weight polyethylene fiberhaving a molecular weight of 300,000 or more,(11) the fishing line according to any of the above (1) to (10), whereinthe sheath part is composed of a long fiber braded around the core part,(12) the fishing line according to any of the above (1) to (10), whereinthe sheath part is wound around the core part,(13) the fishing line according to any of the above (1) to (12), whereinthe long fiber in the sheath part and the short fiber in the core partare intertangled,(14) the fishing line according to any of the above (1) to (13), whereinthe outermost layer of the composite yarn or the fishing line composedof a sheath part and a core part is coated with a resin,(15) the fishing line according to any of the above (1) to (14), whichhas a history of a drawing treatment under heating or without heating ina production process,(16) the fishing line according to any of the above (1) to (15), whereinthe long fiber comprises an ultra high molecular weight polyethylenefiber and the short fiber comprises a fluororesin fiber,(17) a method for producing the fishing line according to the above (1),comprising producing a composite yarn with use of a long fiber for thesheath part and another long fiber for the core part, the melting pointof the long fiber for the core part being higher than that of the longfiber for the sheath part, and drawing the composite yarn under heatingto break the long fiber in the core part into short fiber pieces withoutbreaking the long fiber in the sheath part,(18) a method for producing the fishing line according to the above (1),comprising producing a composite yarn with use of a long fiber for thesheath part and another long fiber for the core part, the strength ofthe long fiber for the core part being lower than that of the long fiberfor the sheath part, and drawing the composite yarn under heating orwithout heating to break the long fiber in the core part into shortfiber pieces without breaking the long fiber in the sheath part,(19) the method according to the above (17) or (18), wherein thesingle-yarn fineness of the short or long fiber constituting the corepart is 11 dtex or less,(20) a method for producing the fishing line according to the above (1),comprising producing a composite yarn with use of a long fiber for thesheath part and a spun yarn comprising a short fiber or staple for thecore part, the melting point of the short fiber or staple being higherthan that of the long fiber for the sheath part, and drawing thecomposite yarn under heating or without heating to break the spun yarninto short fiber pieces without breaking the long fiber in the sheathpart,(21) the method according to any of the above (17) to (20), wherein thestrength of the long fiber in the sheath part is higher than 8.8 cN/dtexand the strength of the long fiber or spun yarn in the core part is 4.4cN/dtex or less,(22) the method according to any of the above (17) to (21), wherein thelong fiber comprises an ultra high molecular weight polyethylene fiberand the short fiber comprises a fluororesin fiber,(23) a yarn comprising a composite yarn having a long fiber in a sheathpart and a spun yarn comprising a short fiber in a core part,(24) the yarn according to the above (23), wherein the long fibercomprises an ultra high molecular weight polyethylene fiber and theshort fiber comprises a fluororesin fiber,(25) a use of a staple for producing the fishing line according to theabove (1), and(26) a yarn comprising a composite yarn composed of a core partcomprising a short fiber and a sheath part comprising a synthetic fiberfilament yarn, the core part and the sheath part being integrated viafluff of the short fiber getting between or entangled with the longfiber, the specific gravity of the yarn being adjustable in the range of1.0 or more, and a fishing line comprising the yarn.

Advantageous Effects of Invention

The fishing line of the present invention is a composite yarn composedof a core part comprising a short fiber and a sheath part comprising along fiber which is preferably a synthetic fiber. At the same time, itis a strong fishing line free from undesirable delamination between thecore part and the sheath part which is frequently seen in conventionalcore-sheath fibers.

The fishing line of the present invention is also excellent in abrasionresistance, and therefore can solve problems of conventional fishinglines in reeling up a fish on a hook, for example surface break of theline due to friction against a guide or other member in contact with theline, or slip.

That is, the fishing line of the present invention is an ideal fishingline which has a strong core-sheath structure, does not allow separationor detachment of the core part and the sheath part, is easy to handle,and also is excellent in strength, weatherability, and water resistance.

In addition, the fishing line of the present invention is excellent inbendability and flexibility, and resistant to kink, torsion, curlinessin a reel, and thread jamming on a spool.

Furthermore, the fishing line of the present invention, of which thesurface is not sticky, is free from sticking together in a reel or on abobbin.

Furthermore, the specific gravity of a fishing line taking advantage ofthe yarn of the present invention can be easily adjusted byappropriately choosing the specific gravity of materials for the shortfiber and the long fiber constituting the yarn, the weight ratio of thematerials to be used, and the drawing rate of the composite yarn. Thespecific gravity of an ultra high molecular weight polyethylene fiber,which is a long fiber, is usually less than 1.0. However, if desired,with the use of a short fiber having a specific gravity of 1.0 or more,a fishing line and a yarn having a specific gravity of 1.0 or more caneasily be produced.

Furthermore, the present invention provides a yarn excellent inrobustness, durability, flexibility, etc. and suitable for producingfishing lines, guts, ropes, etc.

DESCRIPTION OF EMBODIMENTS

The fishing line of the present invention is a composite yarn having acore-sheath structure composed of a core part comprising a fiber havinga short fiber length (hereinafter sometimes referred to as a “shortfiber”) and a sheath part comprising a long fiber (hereinafter sometimesreferred to as a “filament yarn”) which is preferably a synthetic fiber.

Preferable examples of the long fiber constituting the sheath part ofthe composite yarn include a filament yarn made of a plurality of atleast one kind of filament selected from the group consisting of amonofilament, a multifilament, and a monomultifilament, etc.

Examples of the synthetic fiber used as the long fiber constituting thesheath part of the composite yarn include synthetic fibers made ofsynthetic resins, such as polyolefin, polyamide, polyester, andpolyacrylonitrile resins. The tensile strength of the synthetic fiberdetermined with a tensile strength tester, for example Strograph Rtensile strength tester manufactured by Toyo Seiki Seisaku-Sho, Ltd.according to JIS L 1013 “testing method for man-made filament yarns”, isusually higher than about 8.8 cN/dtex, preferably about 17.6 cN/dtex orhigher, more preferably about 22.0 cN/dtex or higher, and mostpreferably about 26.5 cN/dtex or higher. The synthetic long fiber ispreferably a monofilament having a fineness of about 11 to 3300 dtex, ora monomultifilament composed of a plurality of monofilaments, preferablyabout 3 to 50 paralleled monofilaments. Alternatively, the syntheticlong fiber is preferably a multifilament composed of a plurality of,preferably about 10 to 600 paralleled monofilaments.

The synthetic long fiber may be composed of a single fiber or two ormore kinds of fibers.

The synthetic fiber is preferably an ultra high strength fiber, andexamples of the ultra high strength fiber include polyolefin fibers suchas ultra high molecular weight polyethylene fibers having a molecularweight of 300,000 or more, preferably 500,000 or more, aromaticpolyamide (aramid) fibers, heterocyclic high-function fibers, and allthe aromatic polyester fibers. Inter alia, polyolefin fibers such asultra high molecular weight polyethylene fibers having a molecularweight of 500,000 or more are preferred. More preferred are ultra highmolecular weight polyethylene fibers having a molecular weight of1,000,000 or more. Examples thereof include, besides homopolymers,copolymers with a lower α olefin having about 3 to 10 carbon atoms, suchas propylene, butene, pentene, hexene, or the like. In the case of thecopolymer of ethylene with the α olefin, the ratio of the latter per1000 carbon atoms is about 0.1 to 20, preferably about 0.5 to 10 onaverage. Copolymers having such a ratio show excellent mechanicalproperties, such as high strength. The method for producing ultra highmolecular weight polyethylene is described in, for example, JP-A-55-5228and JP-A-55-107506.

The synthetic fiber may comprise an ultra high strength fiber and asynthetic fiber other than ultra high strength fibers. The content ofthe synthetic fiber other than ultra high strength fibers relative tothe ultra high strength fiber is about ½ or less, preferably about ⅓ orless, more preferably about ¼ or less by weight.

The ultra high strength fiber used for the composite yarn may be aheterocyclic high-function fiber in which the amide binding site of theabove-mentioned aramid fiber is modified to increase elasticity of thearamid fiber. Examples of the heterocyclic high-function fiber include,for example, fibers made of poly-p-phenylene benzobisthiazole (PBZT),poly-p-phenylene benzobisoxazole (PBO), and the like. The heterocyclichigh-function fiber can be produced by synthesizing PBZT or PBO resin,dissolving the obtained resin in a suitable solvent, and subsequent dryspinning and drawing. Examples of the solvent include anisotropicliquids, such as methylsulfonic acid, dimethylacetamide-LiCl, and thelike.

Since the required strength and specific gravity of such a compositeyarn vary with the method of fishing, the ratio of the ultra highstrength long fiber in the sheath part relative to the whole compositeyarn cannot be simply mentioned. However, higher strength of compositeyarns is preferred, which means that a higher ratio of the ultra highstrength long fiber is also preferred. The requisite specific gravity ofthe composite yarn also must be achieved, and therefore, it is preferredto increase the ratio of the ultra high strength long fiber to theextent allowed by the requisite specific gravity. Specifically, thepercentage of the ultra high strength long fiber in the sheath part ofthe composite yarn of the present invention relative to the wholecomposite yarn is preferably about 12% by weight or more, preferablyabout 35 to 95% by weight, and most preferably about 60 to 95% byweight.

As the long fiber constituting the sheath part of the present invention,a plurality of monofilaments, multifilaments, or monomultifilaments areused in a paralleled or twisted form. In the case of a twisted yarn, thetwist coefficient K is about 0.2 to 1.5, preferably about 0.3 to 1.2,and more preferably about 0.4 to 0.8.

The sheath part of the fishing line of the present invention usually hasa structure in which a yarn made of plurality of filaments (long fibers)paralleled or twisted is braided or wound around the core part. In thecase of a braided yarn, the braiding angle is preferably about 5° to90°, more preferably about 5° to 50°, and more preferably about 20° to30°.

The short fiber constituting the core part of the composite yarn is ashort fiber having a fiber length of about 5 to 500 mm, preferably about10 to 300 mm, and more preferably a short fiber (staple) having a fiberlength of about 15 to 200 mm.

The short fiber comprised in the core yarn constituting the core part ofthe composite yarn preferably has a specific gravity of 1.0 or more.When a long fiber of which the specific gravity is less than about 1.0is used for the sheath part, using a short fiber of which the specificgravity is about 1.0 or more for the core part enables adjustment of thespecific gravity of the composite yarn without limitation to thespecific gravity of the material constituting the sheath part. Such acomposite yarn is advantageous because the specific gravity of a fishingline can be delicately adjusted depending on the weather or tide.

The short fiber which constitutes the core part of the composite yarn isproduced by, for example, cutting a long fiber into pieces of apredetermined length. Also, the short fiber can be produced by variousmethods: cutting a filament into staples of a predetermined length,twisting staples to form a spun yarn and drawing the yarn to obtainirregularly broken fiber pieces, or drawing a filament yarn, such as amultifilament and monomultifilament to obtain irregularly broken fiberpieces, or the like.

It is more preferred that the short fiber which constitutes the corepart forms a plurality of single yarns and that the yarns are arrangedin a staple-like form, sequentially arranged in a longitudinaldirection, intertangled or intertwisted inside the sheath part. Interalia, preferred is a fishing line of which the single yarns as the shortfiber form a cotton-like material inside the sheath part. Such a fishingline is excellent in flexibility. The short fiber is preferablycontinuous inside the sheath part.

The short fiber which constitutes the core part of the fishing line maybe a synthetic fiber made of a synthetic resin, for example, polyolefinfiber, such as polyethylene or polypropylene; polyamide fiber, such asnylon 6, nylon 66; polyester fiber, such as polyethylene terephthalate;fluororesin fiber, such as polytetrafluoroethylene; polyacrylonitrilefiber; polyvinyl alcohol fiber, or made up of at least one kind selectedfrom the group consisting of a regenerated fiber, such as rayon oracetate; a metal fiber, such as iron, copper, zinc, tin, nickel, ortungsten; a ceramic fiber; a glass fiber, and the like. Examples of theglass fiber include so-called E-glass excellent in electric andmechanical properties, C-glass excellent in chemical resistance,ECR-glass obtained by reducing the alkali content of C-glass and addingtitanium and zinc flux thereto, and also A-glass, L-glass, S-glass, andYM31-A-glass. Inter alia, the glass fiber used by the present inventionis preferably a glass free from boron oxide and fluorine, and has acomposition represented by SiO₂—TiO₂—Al₂O₃—RO (R is a divalent metal,such as Ca and Mg) or SiO₂—Al₂O₃—RO (R is the same as above).

Examples of the above-mentioned fluororesin polymer, which usually meansa fiber obtained from a resin having a fluorine atom in the molecule,include polytetrafluoroethylene (PTFE), the copolymer of ethylenetetrafluoride and perfluoroalkyl vinyl ether (PFA), the copolymer oftetrafluoroethylene and hexafluoropropylene (FEP), the copolymer ofethylene and tetrafluoroethylene (ETFE), polychlorotrifluoroethylene(PCTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride(PVDF), and polyvinyl fluoride (PVF).

The strength of the short fiber which constitutes the core part ispreferably about 4.4 cN/dtex or less. The single-yarn fineness of theshort or long fiber constituting the core part is preferably about 11dtex or less. When the single-yarn fineness of the short or long fiberconstituting the core part is within this range, the fishing line is notstiff or hard, and fibers do not come out of the sheath part.

In the fishing line of the present invention, single yarns of the shortfiber which constitutes the core part may be independent, overlapped, orloosely bound and intertangled or intertwisted. The short fiber ispreferably obtained by breaking a long fiber or a spun yarn.

The fishing line of the present invention is a composite yarn composedof a core part comprising a short fiber and a sheath part comprisingpreferably a synthetic long fiber, and preferably has a structure wherefluff of the short fiber constituting the core part gets between orentangled with the long fibers and thereby the friction coefficientbetween the core and sheath layers is increased. In the fishing line ofthe present invention, it is preferred that the short fiber whichconstitutes the core part is intertangled with or enveloped by the longfiber which constitutes the sheath part, via the fluff of the shortfiber. The short fiber in the core part may be bound with a binder tothe extent that the objective of the present invention would not beimpaired. By this treatment, the fluff condition of the short fiber canbe adjusted, and a composite yarn with a smooth surface can be obtained.A publicly known binder may be used for convenience.

The outermost layer of the fishing line, composite yarn, or yarn of thepresent invention may be covered or coated with a resin, preferably anadhesive resin. Examples of the adhesive resin include acrylic resin,urethane resin, unsaturated polyester resin, epoxy resin, fluororesin,vinyl acetate resin, and polyolefin resin.

Next, a process for producing the fishing line of the present inventionwill be described. The fishing line of the present invention ispreferably produced by, for example, the following method (A), (B), or(C).

(A) A production method comprising producing a composite yarn with useof a long fiber for the sheath part and another long fiber for the corepart, the melting point of the long fiber for the core part being higherthan that of the long fiber for the sheath part, and drawing thecomposite yarn under heating to break the long fiber in the core partinto short fiber pieces without breaking the long fiber in the sheathpart. (In this case, the strength of the fiber for the core part ispreferably lower than that of the long fiber for the sheath part.)(B) A production method comprising producing a composite yarn with useof a long fiber for the sheath part and another long fiber for the corepart, the strength of the long fiber for the core part being lower thanthat of the long fiber for the sheath part, and drawing the compositeyarn under heating or without heating to break the long fiber in thecore part into short fiber pieces without breaking the long fiber in thesheath part.(C) A production method comprising producing a composite yarn with useof a long fiber for the sheath part and a spun yarn comprising a shortfiber or staple for the core part, the melting point of the short fiberor staple being higher than that of the long fiber for the sheath part,and drawing the composite yarn under heating or without heating to breakthe long fiber or the spun yarn into short fiber pieces without breakingthe long fiber in the sheath part.

The composite yarn is produced by winding a long fiber around the corepart constituted by a core yarn to cover the core yarn with the longfiber, or braiding long fibers around the core part constituted by acore yarn. The core yarn is the above-mentioned long fiber or spun yarn.In the case of a braided yarn, the braiding angle is preferably about 5°to 90°, more preferably about 5° to 50°, and more preferably about 20°to 30°. The method for braiding long fibers is not particularly limited,but usually a braiding machine is used. The number of long fibers usedfor braiding is not limited to 4 and in some cases may be 8, 12 or 16.The braiding may be round braiding or square braiding.

A composite yarn composed of a core part comprising a short fiber and asheath part comprising a synthetic fiber filament yarn is drawn underheating or without heating, to give an integrated yarn where fluff ofthe short fiber is entangled with the filament so that the bindingbetween the core and sheath layers is strengthened and that the strengthof the long fiber in the sheath part is improved. Drawing under heatingis preferred. As a drawing temperature, a temperature between theorientation temperature of the synthetic resin which constitutes thelong fiber and about the melting point of the resin is adopted,depending on the material of the long fiber. When the sheath part isconstituted by a long fiber comprising two or more kinds of syntheticresins, the drawing temperature is suitably selected by experiment.Therefore, the drawing temperature cannot be simply mentioned, but thetemperature of the long fiber in drawing is usually about 120 to 300°C., more preferably about 130 to 200° C., and most preferably about 130to 170° C. The drawing rate varies with the types of the short fiber andthe long fiber, and the composition ratio in the composite yarn, but isabout 1.05 to 10, preferably about 1.2 to 8, and most preferably about1.3 to 5. The drawing rate is the ratio of the take-over speed to thefeed speed of the yarn in drawing as represented by the followingformula.

drawing rate=(take-over speed)/(feed speed).

The drawing may be performed in one step or two or more steps. Beforedrawing a composite yarn, an oil agent is provided to the yarn. Themethod is not particularly limited, and publicly known methods may beemployed.

When the composite yarn is composed of a core part made of a spun yarnand a sheath part made of a synthetic long fiber, drawing treatmentincreases the tensile strength of the filament constituting the sheathpart and strengthens the entanglement between the core and sheathlayers, giving a strong yarn excellent in abrasion resistance. Indrawing a composite yarn of which the core part comprises a staple yarn,when a drawing rate is higher than a certain value as described above,the staple yarn in the core part is partially and irregularly broken toforma cotton-like material, giving a yarn excellent in bendability andflexibility.

According to the production method of the present invention, even when acomposite yarn composed of a core part comprising a short fiber and asheath part comprising a synthetic fiber filament yarn does not compriseany adhesive resin, an integrated yarn excellent in bendability,flexibility, and abrasion resistance can be obtained. A fishing linemade of the yarn has effects of resistance to kink, torsion, curlinessin a reel, and thread jamming on a spool. Furthermore, the yarn, ofwhich the surface is not sticky, has beneficial effects of being freefrom sticking together in a reel or on a bobbin when used as a fishingline. However, if needed, the periphery of the yarn of the presentinvention may be coated with an adhesive resin to the extent that theobjective of the present invention would not be impaired. Coating theperiphery of a yarn with an adhesive resin increases the strength of theyarn and at the same time fills gaps on the yarn surface to provide thefishing line with a smooth surface.

The fishing line or composite yarn of the present invention maybeimmersed in a bath of an emulsion, dispersion, or solution of anadhesive resin, squeezed between nip rollers to remove excess adhesiveresin, and then dried so that the periphery (outermost layer) getscovered with the adhesive resin. The periphery of the composite yarn maybe coated with the adhesive resin first and subsequently subjected to adrawing step. Examples of the adhesive resin include, as describedabove, acrylic resin, urethane resin, unsaturated polyester resin, epoxyresin, fluororesin, and vinyl acetate resin.

In the present invention, the short fiber, the filament (long fiber),the adhesive resin, and the like may additionally contain a colorant, astabilizer, a plasticizer, a thickener, a lubricant or the like, or twoor more thereof, to the extent that the objective of the presentinvention would not be impaired.

The yarn of the present invention may be used for any application whereabrasion resistance, durability, weatherability, or water resistance isrequired. Specific examples of the application include various leisuregoods, tools for fishery, such as a fishing line, a longline for tunafishing, a rope, a gut, a kite string, a yarn for removing weeds, asurgical suture, etc.

Examples

Hereinafter, the invention will be described by referring to theexamples below. The tensile strength in the Examples was determined by amethod according to JIS L 1013 “Testing methods for man-made filamentyarns” with a Strograph R tensile strength tester manufactured by ToyoSeiki Seisaku-Sho, Ltd. The break elongation was determined by a methodaccording to JIS L 1013 “Testing methods for man-made filament yarns”with a universal testing machine “Autograph AG-100kNI” (manufactured byShimadzu Corporation) . The fineness was determined according to JIS L1013, Section 7.3. To judge the break status of the core yarn, theentire yarn was cut at right angle to the longitudinal direction, thecore yarn was pulled out from a cut surface, and whether a short pieceof the core yarn was obtained or not was observed. In the tables, “Good”means that not the entire core yarn but short pieces of the core yarnwere pulled out (from a cut surface) with some resistance, whereas“Poor” means that the entire core yarn was easily pulled out in anunbroken state and that the core and the sheath was easily separated.

Example 1

Around a 66-d spun yarn made of a polyester staple (trade name: EsterSpun Yarn El00FBN80/1C, manufactured by Unitika Fiber Co., Ltd.) as acore yarn, eight 75-d filaments made of an ultra high molecular weightpolyethylene fiber (trade name: Dyneema SK71 85T-70-410, manufactured byTOYOBO Co., Ltd.) were round braided into an 826-dtex yarn. The obtainedyarn was separately drawn at a drawing rate of 1.0, 1.3, 1.5, or 1.8 ata drawing temperature of 140° C. In each case, the fineness, straightline strength, straight line break elongation, knot strength, knot breakelongation, and specific gravity of the obtained yarn; and the breakstatus of the core yarn are shown in Table 1.

TABLE 1 Drawing rate 1.0 1.3 1.5 1.8 Fineness (dtex) 826 637 558 461Break status Good Good Good Good Straight line strength (N) 195.24188.97 162.79 112.58 Straight line break elongation (%) 6.8 5.0 3.9 3.1Knot strength (N) 65.11 60.11 58.06 48.54 Knot break elongation (%) 4.23.1 2.2 1.7 Specific gravity 1.01 1.01 1.01 1.01

As Table 1 clearly shows, at any drawing rate, the core yarn was broken.

Example 2

Around a 630-d glass bulky yarn (trade name: TDE70, manufactured byUnitika Glass Fiber Co., Ltd.) as a core yarn, eight 200-d filamentsmade of an ultra high molecular weight polyethylene fiber (trade name:Dyneema SK71 220T-192-410, manufactured by TOYOBO Co., Ltd.) were roundbraided into a 2796-dtex yarn. The obtained yarn was separately drawn ata drawing rate of 1.0, 1.2, 1.7, or 2.0 at a drawing temperature of 140°C. In each case, the fineness, straight line strength, straight linebreak elongation, knot strength, knot break elongation, and specificgravity of the obtained yarn; and the break status of the core yarn areshown in Table 2.

TABLE 2 Drawing rate 1.0 1.2 1.7 2.0 Fineness (dtex) 2796 2457 1717 1477Break status Good Good Good Good Straight line strength (N) 258.11290.18 259.39 218.69 Straight line break elongation (%) 8.7 5.1 3.5 2.8Knot strength (N) 132.49 147.10 117.29 90.52 Knot break elongation (%)6.8 4.6 2.6 2.0 Specific gravity 1.17 1.17 1.17 1.17

As Table 2 clearly shows, at any drawing rate, the core yarn was broken.

Example 3

Around a 203-d glass filament yarn (trade name: Glass YarnD450 1/2 4.4S,manufactured by Unitika Glass Fiber Co., Ltd.) as a core yarn, eight200-d filaments made of an ultra high molecular weight polyethylenefiber (trade name: Dyneema SK71 220T-192-410, manufactured by TOYOBOCo., Ltd.) were round braided into a 2355-dtex yarn. The obtained yarnwas separately drawn at a drawing rate of 1.0, 1.3, 1.5, or 1.8 at adrawing temperature of 140° C. In each case, the fineness, straight linestrength, straight line break elongation, knot strength, knot breakelongation, and specific gravity of the obtained yarn; and the breakstatus of the core yarn are shown in Table 3.

TABLE 3 Drawing rate 1.0 1.3 1.5 1.8 Fineness (dtex) 2355 1859 1653 1341Break status Poor Good Good Good Straight line strength (N) 410.03362.06 357.94 275.17 Straight line break elongation (%) 4.8 3.8 3.1 2.8Knot strength (N) 132.59 88.26 100.42 100.22 Knot break elongation (%)3.2 2.8 2.5 2.6 Specific gravity 1.05 1.05 1.05 1.05

As Table 3 clearly shows, in the case where a glass yarn (long fiber)was used as a core yarn and a long fiber was used for braiding as asheath part, the core yarn was not broken at a drawing rate of 1.0, andbroken when drawn at a rate of 1.3 or more.

The yarn drawn at 1.5 had a higher knot strength, despite the lowerfineness, than the yarn drawn at 1.3. The reason is considered to bethat the glass yarn in the core part was drawn at a higher rate andfavorably broken.

Example 4

Around a 396-d fluororesin filament (trade name: Hastex FEP440dT/48f,manufactured by TOYO POLYMER Co., Ltd.) as a core yarn, eight 100-dfilaments made of an ultra high molecular weight polyethylene fiber(trade name: Dyneema SK71 110T-96-410, manufactured by TOYOBO Co., Ltd.)were round braided into a 1420-dtex yarn. The obtained yarn wasseparately drawn at a drawing rate of 1.0, 1.3, 1.5, or 1.8 at a drawingtemperature of 140° C. In each case, the fineness, straight linestrength, straight line break elongation, knot strength, knot breakelongation, and specific gravity of the obtained yarn; and the breakstatus of the core yarn are shown in Table 4.

TABLE 4 Drawing rate 1.0 1.3 1.5 1.8 Fineness (dtex) 1420 1102 938 778Break status Poor Good Good Good Straight line strength (N) 219.67193.12 167.37 139.47 Straight line break elongation (%) 6.3 3.9 3.1 3.0Knot strength (N) 70.29 61.79 59.72 46.04 Knot break elongation (%) 3.22.8 2.1 1.9 Specific gravity 1.18 1.18 1.18 1.18

1-25. (canceled)
 26. A method for producing a fishing line comprising acomposite yarn having a long fiber in a sheath part and a short fiber ina core part, comprising producing a composite yarn with use of a longfiber for the sheath part and another long fiber for the core part, themelting point of the long fiber for the core part being higher than thatof the long fiber for the sheath part, and drawing the composite yarnunder heating to break the long fiber in the core part into short fiberpieces without breaking the long fiber in the sheath part.
 27. A methodfor producing a fishing line comprising a composite yarn having a longfiber in a sheath part and a short fiber in a core part, comprisingproducing a composite yarn with use of a long fiber for the sheath partand another long fiber for the core part, the strength of the long fiberfor the core part being lower than that of the long fiber for the sheathpart, and drawing the composite yarn under heating or without heating tobreak the long fiber in the core part into short fiber pieces withoutbreaking the long fiber in the sheath part.
 28. The method according toclaim 26, wherein the single-yarn fineness of the short or long fiberconstituting the core part is 11 dtex or less.
 29. The method accordingto claim 27, wherein the single-yarn fineness of the short or long fiberconstituting the core part is 11 dtex or less.
 30. A method forproducing a fishing line comprising a composite yarn having a long fiberin a sheath part and a short fiber in a core part, comprising producinga composite yarn with use of a long fiber for the sheath part and a spunyarn comprising a short fiber or staple for the core part, the meltingpoint of the short fiber or staple being higher than that of the longfiber for the sheath part, and drawing the composite yarn under heatingor without heating to break the spun yarn into short fiber pieceswithout breaking the long fiber in the sheath part.
 31. The methodaccording to claim 26, wherein the strength of the long fiber in thesheath part is higher than 8.8 cN/dtex and the strength of the longfiber or spun yarn in the core part is 4.4 cN/dtex or less.
 32. Themethod according to claim 27, wherein the strength of the long fiber inthe sheath part is higher than 8.8 cN/dtex and the strength of the longfiber or spun yarn in the core part is 4.4 cN/dtex or less.
 33. Themethod according to claim 30, wherein the strength of the long fiber inthe sheath part is higher than 8.8 cN/dtex and the strength of the longfiber or spun yarn in the core part is 4.4 cN/dtex or less.
 34. Themethod according to claim 26, wherein the long fiber comprises an ultrahigh molecular weight polyethylene fiber and the short fiber comprises afluororesin fiber.
 35. The method according to claim 27, wherein thelong fiber comprises an ultra high molecular weight polyethylene fiberand the short fiber comprises a fluororesin fiber.
 36. The methodaccording to claim 30, wherein the long fiber comprises an ultra highmolecular weight polyethylene fiber and the short fiber comprises afluororesin fiber.